The discovery of superconductivity in 3d transition-metal compounds with strong magnetism is interesting but rare. Especially for Mn-based compounds, there exist only very limited materials that show superconductivity. Here, the discovery of superconductivity is reported with an onset transition temperature up to 14.2 K in a Mn-based material MnB₄, which is the highest value among the stoichiometric Mn-based superconductors. By applying high pressure, the continuous suppression of a weak semiconducting behavior and the occurrence of superconductivity after ≈30 GPa are found. With further increasing pressure, the superconducting transition temperature (T_c) is gradually enhanced and reaches the maximum onset transition value of ≈14.2 K at 150 GPa. The synchrotron X-ray diffraction data reveal the unchanged monoclinic (S.G: P2₁/c) symmetry but an unusual crossover of the lattice parameters b and c in a certain pressure region as confirmed by the theoretical calculation. The findings show a promising way to explore high T_c superconductivity by combining the 3d-transition metal magnetic elements and light elements.

中文翻译：

---

在压力下，MnB4 中的超导性高达 14.2 K


在具有强磁性的 3维过渡金属化合物中发现超导性很有趣，但很少见。特别是对于 Mn 基化合物，只有非常有限的材料表现出超导性。在这里，报道了超导性的发现，在 Mn 基材料 MnB₄ 中，起始转变温度高达 14.2 K，这是化学计量 Mn 基超导体中的最高值。通过施加高压，可以发现弱半导体行为的持续抑制和 ≈30 GPa 后超导性的发生。随着压力的进一步增加，超导转变温度 （T_c） 逐渐提高，并在 150 GPa 时达到 ≈14.2 K 的最大起始转变值。同步辐射 X 射线衍射数据揭示了不变的单斜晶系 （S.G： P2₁/c） 对称性，但晶格参数 b 和 c 在某个压力区域发生了不寻常的交叉，这被理论计算所证实。研究结果显示了一种通过结合 3d 过渡金属磁性元件和轻元素来探索高 T_c 超导性的有前途的方法。